Means for cooling machine gun barrels



April 19, 1949. P. R. DE PERMENTIER- 2,467,372

y MEANS FOR COOLING MACHINE GUN BARRELS Y Filed Aug. 6, 1946 2 sheets-sheet 1 April I9, 1949. v P. R. DE PERMENTIER V 2,467,372 MEANS Fon COOLING MACHINE GUN BAIgRjELs Filed Aug, e, 1946A z sets-sheet 2 Patented Apr. 19,y 1949 MEANS FOR COOLING BARR 7 Claims.

The invention described herein may be manufactured and used by or for the Goverment for governmental purposes, without the payment to me of any royalty'thereon.

This invention relates to means for cooling machine gun barrels. It contemplates the provision of such a device designed to force a current or draft of air between the barrel jacket and the barrel from the breech end of the barrel to the muzzle end and so control it under all conditions of use of vthe gun as to produce maximum cooling effects, resulting in more reliable operation of the gun and longer life of the barrel.

I am aware attempts have been made to secure an induced or forced draft through thebarrel jacket during firing. In many cases of which I am aware, when forced draft is sought and depended upon entirely, the jacket structure obstructs cooling during idle periods, and in some cases it was found that the barrel life was prolonged if the cooling jacket were omitted entirely, in that, as intimated, the cooling jacket prevented the cooling of the barrel by radiation and natural convection during idle periods. 'In View of these conditions the main object of the invention is to, provide a structure which cornbines the effect of forced or induced circulation through the jacket during ring, with a substantially unobstructed cooling radiation by convection during idle periods.

The invention contemplates the provision of a practical structure wherein during firing, air is excluded from the barrel except .only that under forced draft from the breech portion to the muzzle end, the arrangement being such that when ring ceases, normal cooling conditions are reestablished.

Two forms of the invention 'are illustrated and described, one in which the shutter tube or sleeve is held depressed during ring by the action of a vacuum formed at the end of the barrel jacket. In thev other form the sleeve, after being depressed by initial firing, is h eld in latched or depressed position so long as firing continues, but .is automatically released when firing ceases. In both cases the forced draft is around the barrel and through the sleeve and barrel jacket from the breech portion to the muzzle end of the jacket during firing, the holes in the jacket, except those insuring intake at its breech end, and outlet at the muzzle end, being closed.

In the drawings illustrating the invention:

Figure lis a longitudinal central section of so much of a gun bar-rel and barrel jacket as is nec- MACHINE GUN ELS Paul R. De Permentier, Liege, Belgium Application August 6, 1946, Serial No. 688,657

(Cl. Sil-14.1)

(Granted under the act of March 3, 1883, as amended April 30, 1928; 370 O. G. 757) essary to show my improvement, the parts being in normal position; I

Figure 2 is a similar view, the parts being in the position assumed during firing;

Figure 3 is a cross section on line 3-3 of Figure 1;

Figure 4 is a longitudinal section showing a somewhat modified structure, the parts being in normal position;

Figure 5 is a view similar to Figure 4 showing the parts in position they assume during firing;

Figure 6 is a cross section about on the line 6--6 of Figure 4;

Figure 7 is a cross section on line I- of Figure 5; and

Figure 8 is a schematic perspective view showing a machine gun trigger, there being associated therewith an example of a mechanism that is operative in response to the trigger action to control the movements of the sleeve illustrated in the form shown in Figures 4 and 5.

Referring to the drawings and particularly to Figures 1, 2, and 3, numeral I designates a breech ring to which is threadedly attached a barrel tube or jacket 2, as at 3, and through which extends the barrel 4. The jacket is provided with numerous holes 5 distributed throughout its length from the rear end to a point near the front of the jacket, the breech openings 5', in the present instance, being, somewhat larger than the others and which are air-intake openings through which air is drawn during the firing of the gun and when forced draft is resorted to.

To the end of the barrel jacket 2, as at 6, is threaded a nozzle 'I having an outwardly aring mouth and provided through the nozzle and surrounding the muzzle end of the barrel are a number of holes 'I' for the passage of air under conditions now to be described.

Within the jacket 2 and having suitable clearance between the parts, is a cylindrical sleeve or shutter 8 provided with holes 9 corresponding to the holes in the jacket and adapted to be brought into and out of registry with the jacket holes in accordance with the intended operation of the device. The rear threaded end 'of the nozzle 'i is so proportioned relative to the inner diameter of the jacket as to form a denite shoulder III, which together with the thickened end of the sleeve 8, forms a chamber 8 and abutments for the spring I I which occupies the chamber and surroundsthe end of the gun barrel. The inner peripheral edge of the sleeve end is shaped to form a seat I2 upon which normally seats a valve I3 secured to the gun barrel. The rear end of the sleeve 8 terrel jacket and those in the sleeve should accurately register under normal cooling conditions and be closed during continuous firing -or under forced draft conditions, the arrangement of the holes in the jacket is changed somewhat from the usual arrangement, in that they are in line longitudinally and so spaced that the allotted movement `0f lthe sleeve will properly cover and uncover them.

I claim:

1. Forced draft cooling means for use with automatic machine guns, comprising a barrel jacket having air outlet openings in its breech end and air olutlet openings in its muzzle end and intermediate heat radiating openings in its Wall, normally open shutter means movable with respect to said jacket and. responsive to gun re to close said intermediate openings, and means for returning the shutter means to normal open position upon cessation of gun re.

2. Forced draft cooling means for use With automatic machine guns, comprising a lbarrel jacket provided with air inlet openings in its breech end and air outlet openings in. its muzzle end and intermediate heat radiating openings in its Wall, a sleeve longitudinally movable in said jacket in close proximity to the inner periphery of the jacket and provided with openings arranged to initially register with said intermediate openings when the gun is not ring and responsive to gun fire to bring said sleeve to move its openings out of registry with the intermediate openings in the jacket to thereby close said intermediate openings, and means for returning the sleeve to its initial position upon cessation of iire.

3. Forced draft cooling means for use with automatic machine guns, comprising in combination With a gun barrel a barfrel jacket surrounding said gun barrel and provided with inlet openings in its breech end and heat radiating openings in its Wall, a nozzle secured to the muzzle end of the jacket and surrounding the end of the gun barrel, said nozzle having air outlet openings therethrough surrounding the end of the gun barrel and communicating with the interior of the jacket, a sleeve longitudinally movable in said jacket and having openings initially registering With the heat radiating openings in the jacket when the gun is not ring, a oW-retarding surface Xed to said sleeve and responsive to suction created in said nozzle during firing to move the sleeve to close the intermediate jacket openings,

vand means for returning the sleeve to its initial position when firing ceases.

4. The invention of claim 3 characterized in that the means for returning the sleeve to normal position is a spring interposed between the nozzle and front end of the sleeve.

5. Forced draft cooling means for use with automatic machine guns having a gun barrel comprising a barrel jacket provided with air inlet openings in its breech end and heat radiating openings in its wall, a nozzle secured to the muzzle end of the jacket and constructed and proportioned to surround the muzzle end of a gun barrel,

said nozzle having air outlet openings therethrough arranged to surround the end of such gun barrel and communicating with the interior of the jacket, a sleeve longitudinally movable in said jacket and having openings initially registering with the heat radiating openings in the jacket and also an air inlet opening in its breech end and air orutlet openings at its forward end, a valve element attached to the gun barrel and normally closing said air outlet openings, said sleeve being responsive to suction created in advance of the sleeve during the firing of an attached gun to move said sleeve to close the heat radiating openings in the barrel and simultaneously unseat said valve element to open the air outlet openings in the end of the sleeve, and means for returning the sleeve to its initial position after firing.

6. Forced draft cooling means for use with an automatic machine gun having a barrel Which moves in recoil and counter recoil, comprising a barrel jacket having air inlet openings in its breech end and air outlet openings in its nozzle end and intermediate heat radiating openings in its Wall, a sleeve longitudinally movable in said jacket in close proximity with the inner periphery of the jacket and provided with openings initially registering with the jacket heat radiating openings, means including a resilient member adapted for actuation by a barrel for exerting p-ressure upon the sleeve upon initial recoil of the barrel to move said sleeve to position to close the heat radiating openings in the jacket, means for latching the sleeve in such position, and trigger operated means for holding the latching means in sleeve latching position during iiring of the gun, and also operating to release the sleeve latching means when firing ceases to penmit the sleeve to return to normal position wherein normal cooling is resumed, and means for automatically returning the sleeve to normal position when released from the latching means.

'7. The invention of claim 6 characterized in that the means for latching the sleeve comprises a slot in said sleeve, a spring catch carried by the barrel jacket and having a portion adapted to enter said slot when the sleeve is moved rearwardly, said trigger-operated means for holding the sleeve latching means in latching position including a reciprocable member having operable connection with the gun trigger and engaging the spring catch to hold it in latching position When said member is moved in one direction and to release said catch When moved in the opposite direction.

PAUL R. DE PERB/ENTIER.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATESI PATENTS Number Name Date 1,296,193 Johnston Mar. 4, 1919 1,308,016 Clark June 24, 1919 1,551,617 Pohlmann Sept. 1, 1925 

